From: Wei Gao Date: Fri, 13 Jun 2025 15:18:38 +0000 (-0400) Subject: ext2: Handle fiemap on empty files to prevent EINVAL X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a099b09a3342a0b28ea330e405501b5b4d0424b4;p=thirdparty%2Flinux.git ext2: Handle fiemap on empty files to prevent EINVAL Previously, ext2_fiemap would unconditionally apply "len = min_t(u64, len, i_size_read(inode));", When inode->i_size was 0 (for an empty file), this would reduce the requested len to 0. Passing len = 0 to iomap_fiemap could then result in an -EINVAL error, even for valid queries on empty files. Link: https://github.com/linux-test-project/ltp/issues/1246 Signed-off-by: Wei Gao Signed-off-by: Jan Kara Link: https://patch.msgid.link/20250613152402.3432135-1-wegao@suse.com --- diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 30f8201c155f4..177b1f852b63a 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -895,9 +895,19 @@ int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len) { int ret; + loff_t i_size; inode_lock(inode); - len = min_t(u64, len, i_size_read(inode)); + i_size = i_size_read(inode); + /* + * iomap_fiemap() returns EINVAL for 0 length. Make sure we don't trim + * length to 0 but still trim the range as much as possible since + * ext2_get_blocks() iterates unmapped space block by block which is + * slow. + */ + if (i_size == 0) + i_size = 1; + len = min_t(u64, len, i_size); ret = iomap_fiemap(inode, fieinfo, start, len, &ext2_iomap_ops); inode_unlock(inode);